Oracle wait event: rdbms ipc message

select
   prc.pname,
   prc.background,
   to_char( ses.wait_time_micro       / 1000 / 1000, '999990.999') wait_time_s,
   to_char( ses.time_remaining_micro  / 1000 / 1000, '999990.999') time_remaining_s,
   to_char((ses.wait_time_micro        +
            ses.time_remaining_micro) / 1000 / 1000, '999990.999') time_sum_s,
   ses.p1text,
   ses.p1,
   ses.schemaname,
   ses.osuser
from
   v$session ses                                join
   v$process prc on ses.paddr = prc.addr
where
   ses.event = 'rdbms ipc message'
order by
   ses.wait_time_micro desc